Donaldson is an unincorporated community and census-designated place (CDP) in West Township, Marshall County, Indiana, United States. It is home to Ancilla College and the American motherhouse of the Poor Handmaids of Jesus Christ.
Donaldson (also historically spelled "Donelson") was laid out in 1871. A post office has been in operation there since 1871.
Donaldson is located in western Marshall County at . U.S. Route 30 runs along the northern edge of the community, leading east to Plymouth, the county seat, and west to Grovertown.
According to the U.S. Census Bureau, the Donaldson CDP has an area of , all land.
The United States Census Bureau first delineated Donaldson as a census designated place in the 2022 American Community Survey.